Essar prepares 75-well campaign at Raniganj East

Vol 13, PW 4 (30 Jul 09) Exploration & Production

In around two months from now Essar Oil will begin to drill 75 wells at its CBM block RG (E)-CBM-2001/1 in West Bengal, also known as Raniganj East.

Two rigs will be deployed to drill these wells during the two-year Phase-II period, which began in May this year. Essar owns one of the rigs; the other is yet to be hired.

PETROWATCH learns actual drilling will begin in October or November after the summer rains. “Monsoon rains are heavy in this region,â€‌ reports Essar.

“Land is water logged and it is impossible to mobilise rigs.â€‌ In the intervening period from now till October, Essar says it is ordering and assembling materials needed for the drilling operation.

On site, Essar has begun â€کde-watering’ 15 test wells drilled and hydro-fractured during Phase-I, which ended mid-May. “About 150 to 200 cm/d of water is being produced from each well,â€‌ adds Essar.

Along with the water, each well is also yielding between 150 to 300cm/d of methane at a flowing pressure of between 20 and 25-psi, which Essar is flaring. Happy with the rate of water flow, Essar takes this as confirmation that, “permeability in the coal reservoir is very good.

â€‌ Adds Essar: “If permeability was low then we would not have had such a good water flow rate. Four or five of the wells started producing â€کdesorbed’ gas (methane which frees itself from the coal) from the second day itself, indicating good permeability.

â€‌ Over the next four to six months, says Essar, water flow will reduce and methane flow will increase. “Once the relative permeability of gas goes up and water goes down the gas production will leapfrog from the present low numbers.

â€‌ Essar says it is keeping wellhead pressure as low as possible so that methane can separate itself easily from the coal seams and escape effortlessly. “In this respect a CBM operation is just the opposite of a traditional hydrocarbon development project,â€‌ we hear.